/*******************************************************************************
 * Copyright (c) 2004, 2005 Elias Volanakis and others.
?* All rights reserved. This program and the accompanying materials
?* are made available under the terms of the Eclipse Public License v1.0
?* which accompanies this distribution, and is available at
?* http://www.eclipse.org/legal/epl-v10.html
?*
?* Contributors:
?*????Elias Volanakis - initial API and implementation
?*******************************************************************************/
package org.eclipse.gef.examples.shapes.parts;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.List;

import org.eclipse.draw2d.ConnectionLayer;
import org.eclipse.draw2d.Figure;
import org.eclipse.draw2d.FreeformLayer;
import org.eclipse.draw2d.FreeformLayout;
import org.eclipse.draw2d.IFigure;
import org.eclipse.draw2d.MarginBorder;
import org.eclipse.draw2d.ShortestPathConnectionRouter;
import org.eclipse.draw2d.geometry.Rectangle;

import org.eclipse.gef.EditPart;
import org.eclipse.gef.EditPolicy;
import org.eclipse.gef.LayerConstants;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.editparts.AbstractGraphicalEditPart;
import org.eclipse.gef.editpolicies.RootComponentEditPolicy;
import org.eclipse.gef.editpolicies.XYLayoutEditPolicy;
import org.eclipse.gef.requests.ChangeBoundsRequest;
import org.eclipse.gef.requests.CreateRequest;

import org.eclipse.gef.examples.shapes.model.EllipticalShape;
import org.eclipse.gef.examples.shapes.model.ModelElement;
import org.eclipse.gef.examples.shapes.model.RectangularShape;
import org.eclipse.gef.examples.shapes.model.Shape;
import org.eclipse.gef.examples.shapes.model.ShapesDiagram;
import org.eclipse.gef.examples.shapes.model.commands.ShapeCreateCommand;
import org.eclipse.gef.examples.shapes.model.commands.ShapeSetConstraintCommand;

/**
 * EditPart for the a ShapesDiagram instance.
 * <p>This edit part server as the main diagram container, the white area where
 * everything else is in. Also responsible for the container's layout (the
 * way the container rearanges is contents) and the container's capabilities
 * (edit policies).
 * </p>
 * <p>This edit part must implement the PropertyChangeListener interface, 
 * so it can be notified of property changes in the corresponding model element.
 * </p>
 * 
 * @author Elias Volanakis
 */
class DiagramEditPart extends AbstractGraphicalEditPart 
	implements PropertyChangeListener  {

/**
 * Upon activation, attach to the model element as a property change listener.
 */
public void activate() {
	if (!isActive()) {
		super.activate();
		((ModelElement) getModel()).addPropertyChangeListener(this);
	}
}

/* (non-Javadoc)
 * @see org.eclipse.gef.editparts.AbstractEditPart#createEditPolicies()
 */
protected void createEditPolicies() {
	// disallows the removal of this edit part from its parent
	installEditPolicy(EditPolicy.COMPONENT_ROLE, new RootComponentEditPolicy());
	// handles constraint changes (e.g. moving and/or resizing) of model elements
	// and creation of new model elements
	installEditPolicy(EditPolicy.LAYOUT_ROLE,  new ShapesXYLayoutEditPolicy());
}

/* (non-Javadoc)
 * @see org.eclipse.gef.editparts.AbstractGraphicalEditPart#createFigure()
 */
protected IFigure createFigure() {
	Figure f = new FreeformLayer();
	f.setBorder(new MarginBorder(3));
	f.setLayoutManager(new FreeformLayout());

	// Create the static router for the connection layer
	ConnectionLayer connLayer = (ConnectionLayer)getLayer(LayerConstants.CONNECTION_LAYER);
	connLayer.setConnectionRouter(new ShortestPathConnectionRouter(f));
	
	return f;
}

/**
 * Upon deactivation, detach from the model element as a property change listener.
 */
public void deactivate() {
	if (isActive()) {
		super.deactivate();
		((ModelElement) getModel()).removePropertyChangeListener(this);
	}
}

private ShapesDiagram getCastedModel() {
	return (ShapesDiagram) getModel();
}

/* (non-Javadoc)
 * @see org.eclipse.gef.editparts.AbstractEditPart#getModelChildren()
 */
protected List getModelChildren() {
	return getCastedModel().getChildren(); // return a list of shapes
}

/* (non-Javadoc)
 * @see java.beans.PropertyChangeListener#propertyChange(PropertyChangeEvent)
 */
public void propertyChange(PropertyChangeEvent evt) {
	String prop = evt.getPropertyName();
	// these properties are fired when Shapes are added into or removed from 
	// the ShapeDiagram instance and must cause a call of refreshChildren()
	// to update the diagram's contents.
	if (ShapesDiagram.CHILD_ADDED_PROP.equals(prop)
			|| ShapesDiagram.CHILD_REMOVED_PROP.equals(prop)) {
		refreshChildren();
	}
}

/**
 * EditPolicy for the Figure used by this edit part.
 * Children of XYLayoutEditPolicy can be used in Figures with XYLayout.
 * @author Elias Volanakis
 */
private static class ShapesXYLayoutEditPolicy extends XYLayoutEditPolicy {
	
	/* (non-Javadoc)
	 * @see ConstrainedLayoutEditPolicy#createChangeConstraintCommand(ChangeBoundsRequest, EditPart, Object)
	 */
	protected Command createChangeConstraintCommand(ChangeBoundsRequest request,
			EditPart child, Object constraint) {
		if (child instanceof ShapeEditPart && constraint instanceof Rectangle) {
			// return a command that can move and/or resize a Shape
			return new ShapeSetConstraintCommand(
					(Shape) child.getModel(), request, (Rectangle) constraint);
		}
		return super.createChangeConstraintCommand(request, child, constraint);
	}
	
	/* (non-Javadoc)
	 * @see ConstrainedLayoutEditPolicy#createChangeConstraintCommand(EditPart, Object)
	 */
	protected Command createChangeConstraintCommand(EditPart child,
			Object constraint) {
		// not used in this example
		return null;
	}
	
	/* (non-Javadoc)
	 * @see LayoutEditPolicy#getCreateCommand(CreateRequest)
	 */
	protected Command getCreateCommand(CreateRequest request) {
		Object childClass = request.getNewObjectType();
		if (childClass == EllipticalShape.class || childClass == RectangularShape.class) {
			// return a command that can add a Shape to a ShapesDiagram 
			return new ShapeCreateCommand((Shape)request.getNewObject(), 
					(ShapesDiagram)getHost().getModel(), (Rectangle)getConstraintFor(request));
		}
		return null;
	}
	
}

}